Chemical Characterization of Fibers from Herbaceous Plants Commonly Used for Manufacturing of High Quality Paper Pulps

The present work aims at the chemical characterization of several non-woody fibers from herbaceous plants used for manufacturing high quality paper pulps, with especial emphasis in the composition of lignin and lipophilic compounds. Among the fibers studied are bast fibers from flax, hemp, kenaf and jute and leaf fibers from abaca and sisal. Flax and hemp showed the lowest lignin content (< 5%). However, they present a very low lignin S/G ratio (0.3 and 0.6, respectively) that makes them difficult to be delignified. On the other hand, kenaf, jute, sisal and abaca present higher lignin content, but the S/G ratio is higher (from 2.7 to 5.8) which would make them more easily delignifiable. With respect to the lipophilic extractives, flax, hemp, kenaf and jute are characterized by a high content of waxes, hemp having also a high content of sterols and triterpenols. Sisal and abaca are characterized by series of p-hydroxycinnamic acids esterified with long chain fatty alcohols and ωhydroxyfatty acids.